Pull-up hitch for tractors



Jam 20, 1953 G. l.. GusTAFsoN PULL-UP HITCH FOR TRACTQRS Filed Jan. 5, 1949 IN VEN TOR.

Patented Jan. 20, 1953 UNITED STATE-s PATENT OFFICE PULL-UP HITCH FOR TRACTORS George L. Gustafson, Minneapolis, Minn.

Application January 5, 1949, Serial No. 69,272

4 Claims. (Cl. 254-186) 'I'his invention relates to tractor hitches and particularly to a pull-up type of hitch.

It has long been a problem when connecting a tractor to a trailing unit to be drawn, to align the hitching elements of the drawbar and the tractor to form a positive connection therebetween. With most conventional hitches the tractor must be backed up to exactly the right position and thereafter the drawbar lifted manually and the two hitching elements perfectly aligned to make the connection.

It is an object of my invention to provide a novel and improved tractor hitch adapted to be connected to the drawbar of a trailing unit even when said trailing unit and drawbar are disposed a substantial distance behind the tractor, and after connection therewith to pull the trailing unit up to the tractor to permit a positive connection to be made between the tractor and the drawbar.

It is another object to provide a pull-up type of tractor hitch having a flexible cable wound on a winding drum and adapted to be pulled out to permit attachment of the free end of said cable with the drawbar of a trailing unit disposed in spaced relation to said tractor and having a mechanism for thereafter rotating said drum to wind up said capable thereon and pull the trailing unit up to said tractor to permit a positive connection to .be made between the drawbar and the tractor.

It is a further object to provide a pull-up type of tractor hitch having a cable and drum winding mechanism and incorporating a hydraulic plunger system therewith with an ingenious mechanism for converting the short rectilinear stroke-of the plunger to rotary movement for driving the winding drum and also building up the speed of rotation of the drum to permit a relatively large amount of take-up for a slight projection of said plunger.

More specifically, it is an object to provide a cable and drum winding mechanism including a hydraulically actuated plunger for actuating a pull-up type of tractor hitch and incorporating therewith a series of interrelated spirals associated with said plunger and said drum to convert the short rectilinear stroke of the plunger to a relatively large amount of take-up in the cable to produce a highly efficient take-up hitch mechanism.

These and other objects and advantages of my invention will more fully appear from the following description made in connection with the accompanying drawings wherein like reference characters refer to similar parts throughout the several views and in which:

Fig. 1 is a top plan View of my pull-up hitch as attached to the back of a tractor and showing a portion of a drawbar of a trailing unit about to be pulled up to the tractor and showing said drawbar in positively attached position by dotted lines after being pulled up;

Fig. 2 is a fragmentary vertical sectional view taken substantially along the line 2 2 of Fig'. l showing in detail the plunger and spiral driving mechanism for the winding drum and showing the hydraulic ram housing in side elevation;

Fig. 3 is a transverse vertical sectional view taken substantially along the line 3-3 of Fig. 2;

Fig. 4 is a vertical sectional view of the winding drum and internal rotating spiral fixed thereto with the stationary spiral and plunger removed;

Fig. 5 is a longitudinal vertical sectional View of only the stationary spiral; and

Fig. 6 is a fragmentary side elevational view of the outer end portion of the plunger.

Only the rear end of a conventional tractor is shown in Fig. l and is designated by the numeral 9. A winding drum housing I0 is shown securely attached to the rear end 9 of said tractor as by the bolts II. A bell-shaped fair-leader I2 is in the form shown integrally cast on the drum housing I0 and extends rearwardly therefrom. A winding drum I3 having in the form illustrated two sets of cable-receiving grooves I3a and I3b respectively, is journaled in the housing I0 on suitable bearings such as the ball-bearings I4, the details of which will be described later. A pair of cables I5 are respectively wound in the grooves I3a and |319 on the drum I3 and extend outwardly through the fair-leader I2 and have a connection link I6 xed at the outer ends thereof. The connection link IS, as shown in Fig. 1, is adapted to be connected at its outer end to a drawbar I'I, only a fragmentary portion of which is shown in Fig. 1. The link I6 has a pair of longitudinally spaced apertures I 6a and IBb formed therethrough, aperture I6a being adapted to receive a pin extending through the forward vportion of the drawbar I1 to positively connect said drawbar II to the link I6. The rear portion of the fair-leader has a pair of vertically aligned apertures I8 formed therethrough to form a hitching bracket, and a pin is adapted to be inserted through apertures i8 and aperture Iib when aligned therewith to positively connect link IB with the rear extremity 9 of the tractor.

A ram housing I9 is xed on one end of the drum 'housing I 0 as by the cap screws 20 and has an annular bearing support 2| integrally fixed on the inner end thereof. A conventional hydraulic ram (not shown) is mounted within the housing I9 and is connected -by the fluid supply lines 22 with a source of fluid under pressure, such `as the conventional hydraulic pump (not shown) mounted on the tractor. The outer end of the housing I9 is closed Iaround a uid inlet and outlet asby the closure cap 23. A plunger 24 is fixed in direct end to end alignment with the ram and extends through the annular bearing support 2| and is journaled in a suitable bearing 25 mounted in said supper-t 2|; The housing I is closed at its other end as by the cover plate 26 securely held in place by the'cap screws 2'I.

A fixed spiral 28 has its end extremities respectively xed to bearing support 2| and coverplate` 26, as by a pair of attachment plates 28a, each of which is held to its respective support by a plurality of cap screws 23h. The plates 28a may be square in shape and be respectively received in cooperatingl square recesses formed in the platesl 2| and 26 to positively prevent rotation thereof and remove theV torque strain from the cap screws 28h. The cover plate 26 and bearing support 2| respectively. carry the two bearing units I4 on which the rotating winding drum I3 is journaled. A rotating spiral 29 of opposite pitch `from stationary spiral 28' is fixed to the inner.v periphery of the winding drum I3 as by a pair of transversely disposed annular webs 29a and surrounds th'evstationary spiral 28.

The end portion of the plunger 24 extends into the spiral 28 and has a transversely disposed pin 30flxed therein and extending laterally outwardly therebeyond on both sides thereof. A pair of rollers 3| are respectively journaled on the end portions of pin 30 and are disposed adjacent f plunger 24 for engagement in the groove 28e of spiral 28, the pitch of said groove in the form shown being at least 45 to permit'roll'ers on both ends to be received t-herein. A second pair of Irollers 32 are journaled respectively on theextreme outer end portions of said pin 3U and are adapted to -be received in the groove 29h of the rotating spiral l29 which has a pitch substantially equal to the pitch of the groove 28e land sloping in the opposite direction.

Operation hitch, this connection can bev easily'. made. by

merely unwinding the cables I fromthe drum I3 and attaching the outer end of linkv I 6a to t-he forward end of the drawbar I'I. After this connection has been made, thehydraulic :pump of thetractor is controllably operated to actuate the Y Y hydraulic ram in casing I9 and forcibly project the plunger 214 into the stationary spiral 28. The

rollers 3| engaged in the groove28c of stationary. spiral 28 travel yaround .in said groove and causesaid -plunger 24 to rotate in a clockwise direction, as viewed in Fig. 3. This clockwise rotation of plunger 24 causes a similar clockwise lrotation-ofv rotating lspiral 29r at approximately twice the velocity of rotation of said plunger. The rollers 32'engage thespiral 29 in the groove 29h thereof and rotates said drum to wind t-he two cables I5 thereon respectively in the grooves |3a and |317. When the plunger reaches the end cover `26, the link I6 will be drawn into the fair-leader I2 and disposed in position therein so that the aperture I6b can be readily aligned with aper- -tures I8 to permit a connection pin to be dropped therethrough to form a positive connection between the drawbar and the tractor. The fairleader I2 flares outwardly at the inner portion thereof as well as the outer portion. The ilaring at the outer portion serves to guide the cables and link into hitching position, and the flaring on the inner portion serves to guide the cables I5 onto their respective grooves I3a and |3b.

It will be seen'that I have provided a novel and improved pull-up type tractor hitch which is adapted to pull the drawbar of a trailing unit up intov close association with the tractor and facilitate making a positive connection between said drawbar and the tractor, the outer link member of the pull-up mechanism forming a cooperating part in the positive connection ultimately made. Also, it should be noted that the two interrelated spirals of the drum-rotating mechanism provide a particularly ingenious and highly efiicient transmission mechanism for obtaining the desired relatively fast rotation of the drum |3'to produce a relatively large amount of take-up for a short operating stroke of the plunger. This conversion of a small rectilinear movement to a relatively large rotational movement Iand large take-up of the flexible cable is an extremely important part of my invention and permits a trailingunit `which is disposed in an inaccessible position in spaced relation to a tractor to be drawn up to the tractor and a positive hitching connection easily made therebetween. It is also important to note that if a tractor with a heavy load attached is stuck on a slippery surface, the forward hitching pin may be removed and the tractor pulled forwardly onto solid ground to unwind the cable and the trailing unit subsequently pulled up thereto Vby my take-up mechanism, and if necessary, the operation repeated until sufiicient traction is obtainedY to permit normal towing procedure.

Itvshould also be noted that the drawbar with an extremely heavy load thereon may be eased downwardly by releasing only the vforward pin connection of the link I 6 and the hydraulic pressure against the ram mechanism controlled to slowlylower said drawbar to the ground and prevent damage to the drawbar which might be caused by forcible impact against the ground.

It will, of cou-rse, be understood that various changesmay be made 1n the form, details, arrangement -and proportionsof the parts without departing fromv the scope of my invention.

1. For use with a .pull-up type trailer hitch, aA

hollow rotary drum adapted to receive an elongated flexible take-up member thereon, means for journaling said drum,` a longitudinally shiftable powerv driven element, a transmission mechanism including `a spiral fixed to said drum journalling means and having at least a portion- 1y projectible power driven element, whereby rectilinear motion will be converted to rotary motion.

2. For use with a trailer hitch of the pull-up Itype, a supporting structure, a hollow rotary drum journaled on said structure and adapted to have an elongated exible take-up member secured at one end thereto, a longitudinally shiftable power driven element, a transmission mechanism including a spiral forming a driving connection with said winding `drum and a second spiral secured in fixed r-elation to said supporting structure and having its pitch sloped oppositely to the pitch of said rst spiral and disposed -concentrically thereof, said power -driven longitudinally shiftable element being yprojectible concentrically into said two spirals, and an outstanding element connected to said projectible element for simultaneous sliding engagement in said two spirals.

3. The structure set forth in claim 2, and the pitch of said spirals lbeing at least forty-ve degrees sloped in opposite directions.

4. The structure set forth in lclaim 2 and said longitudinally projecting element 'being hydraul-cally actuated.

GEORGE L. GUSTA-FSON.

REFERENCES CITED The following references are of record in the 

